M0: foundation — core, numfmt, formula, functions (478), model, calc, xlsx/csv, engine

Clean-room spreadsheet engine: addresses/values/dates, Excel number formats,
formula parser/printer/reference adjustment, worksheet function library,
copy-on-write workbook model, dependency-driven recalculation with dynamic
arrays, XLSX/CSV I/O, and a command engine (cell entry, clipboard, fill,
formatting, sheets, sort/filter, tables, charts, CF, names, view, file).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/brand/LICENSE-brand.txt

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+ArtCraft brand assets: license
+
+The ArtCraft name, wordmark and mark (the "ArtCraft Marks"), including every file in this
+directory in every color, size and format, are owned by the ArtCraft Team. They are trademarks
+and are NOT open source. They are not covered by SheetCraft's MIT OR Apache-2.0 license, and nothing in
+that license, in NOTICE or in any other file of this repository grants any right to them.
+
+Permission
+
+The ArtCraft Team grants a limited, non-exclusive, non-transferable, revocable, royalty-free
+permission to use the ArtCraft Marks only:
+
+  1. as part of copies of this repository; and
+  2. within SheetCraft itself, its documentation and its official builds, to identify SheetCraft as made
+     by the ArtCraft team and community and to link to getartcraft.com and its community.
+
+Conditions
+
+The permission holds only while every one of these is true:
+
+  - The marks are used exactly as supplied in this directory. Do not redraw, recolor, crop,
+    stretch, rotate, animate, outline or add effects to them, extract parts of them, or combine
+    them with any other name, mark or artwork.
+  - They are used only in the context of SheetCraft, and only to say that the ArtCraft team makes it.
+    They must never suggest that the ArtCraft Team made, sponsors, endorses, certifies or supports
+    any other product, service, fork, modified version, plug-in, organization or person.
+  - Neither the marks nor the ArtCraft name appear in the name, logo, icon, domain, social media
+    handle, app-store listing, advertising or marketing of anything other than SheetCraft.
+
+Forks and modified versions
+
+If you distribute or publish a modified version of SheetCraft, or any work derived from it, you must
+remove the ArtCraft Marks from it (or replace them with your own) and must not call it ArtCraft or
+present it as an ArtCraft product. You may say, in plain text, that your work is based on SheetCraft by
+the ArtCraft team. A fork kept only to propose changes back to this repository may keep the marks
+unchanged.
+
+Everything else
+
+Any use not expressly permitted here needs prior written permission from the ArtCraft Team
+(https://getartcraft.com/). The permission ends automatically for anyone who breaks these terms.
+All other rights are reserved.

docs/brand/artcraft-mark-black.svg

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+<svg xmlns="http://www.w3.org/2000/svg" viewBox="-10 -19.42 136.34 136.34" role="img" aria-label="ArtCraft">
+  <title>ArtCraft</title>
+  <path fill="#0b0b0c" d="M104.28,49.49L81.55,0h-31.23l-3.17,4.76L14.75,53.63,0,75.85l21.55,21.55,63.79-36.94,16.99,37.04,14.01-21.74-12.06-26.27ZM32.89,65.66l32.42-48.87,10.91,23.77-43.32,25.09Z"/>
+</svg>

docs/brand/artcraft-mark.svg

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+<svg xmlns="http://www.w3.org/2000/svg" viewBox="-10 -19.42 136.34 136.34" role="img" aria-label="ArtCraft">
+  <title>ArtCraft</title>
+  <path fill="#4e7bfb" d="M104.28,49.49L81.55,0h-31.23l-3.17,4.76L14.75,53.63,0,75.85l21.55,21.55,63.79-36.94,16.99,37.04,14.01-21.74-12.06-26.27ZM32.89,65.66l32.42-48.87,10.91,23.77-43.32,25.09Z"/>
+</svg>